2024-05-21_PERMIT FILE - C1981010A (8)

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The M12 series of maps depicts the planned Post Mining Topography. The topography depicted meets the definition of approximate original contour, per Statute 34-33-103(3) and Regulation 1.04(13). The proposed topography closely resembles the general surface configuration of the land prior to mining, and blends into and complements the drainage pattern of the surrounding terrain. The variance of post mining elevations and pre-mining elevations are consistent with Trapper’s prior, and successful, reclamation efforts. As such, the Horse Gulch fill qualifies as excess spoil, as defined by Regulation 1.04(45a). This fill was left as a permanent reclamation feature, consistent with the planned post mining land use of Rangeland and Wildlife Habitat. The fill was constructed with overburden, as defined by Regulation 1.04(83). Neither coal mine waste, as defined by Regulation 1.04(22a), nor coal processing waste, as defined by Regulation 1.04(24), were used in the construction of the fill. Topsoil was stripped and salvaged prior to construction, and no organic material was used in its construction. The Horse Gulch area was chosen for excess spoil placement because the area contained neither ephemeral streams, as defined in Regulation 1.04(42), nor intermittent streams, as defined by Regulation 1.04(69). This location allowed construction of a head of hollow fill, as defined by Regulation 1.04(56), which blends with the surrounding topography. Detailed cross sections can be found in Appendix T. The hydrologic balance, as defined by Regulation 1.04(61), is protected with this mine plan. There is no discernible change in the quality or quantity of water inflow to our outflow of the Yampa River Basin. The final cut in any given pit may be open for as long as 18 months as the need to remove coal to allow for continuous stripping operations is not a factor. Final cuts are a logical area to carry inventory. Due to spoil side stripping techniques employed at Trapper, extra room is needed to effectively place the spoils. Taking into consideration that the shortest cycle time in a down-dip dragline operation leaves the pit active for up to 230 days and that the interburden will be cast as far as three previous cuts, it is not possible to regrade the spoils within 180 days after coal removal. For Trapper Mine's contemporaneous regrade criteria, grading will progress such that there will be no more than three un-regraded spoil rows, including the active spoil row, at any one time in each pit. A pictorial view of the double pass stripping operation is shown in Figure 3.5-1. This figure presents a simplification of the Trapper stripping operation and shows graphically why three spoil rows are required. 3-39